Olive oil should be stored in a cool, dark place. Properly stored, olive oil can keep for at least two years. It is, however, at its peak within a year of production, and is its most flavorful for the first two months.
Olive oil should not be stored in the refrigerator. If chilled, olive oil will become cloudy and eventually solidify or crystallize. Should this happen, the oil is perfectly fine; just leave the oil at room temperature for a time to restore it to its natural state.